COPD is not a single disease, it stands for
Chronic Obstructive Pulmonary Disease. It is a common term used for a
host of other respiratory diseases. They are:

A) Emphysema: Emphysema is caused by continued exposure to
environmental pollution, especially tobacco smoke. It destroys the
delicate structure of the lungs by damaging the air sacs or the
alveoli. This results in fewer and larger air sacs which makes it
difficult for the person to inhale and exhale. Larger sacs mean less
usable oxygen which results into breathlessness. Damage from this
disease is irreversible and permanent.

B) Chronic bronchitis: It is a condition where some irritant such
as cigarette smoke causes the lungs to inflame. This inflammation
creates more mucus and the end result is chronic cough and breathing
difficulty.

To start with proper medications, it is important to
know the symptoms of the disease. They are: 1) Cough 2) Mucus 3) Tightness of chest 4) Shortness of breath 5) Wheezing

If you have any of these symptoms, you may consult a physician
immediately. The earlier you start a treatment, the more are your
chances of arresting the damage caused due to COPD. Your physician is
more likely to know the exact damage to your lungs and prescribe
treatment accordingly. But quitting smoking is the best way to nurture
your lungs. Your lung function may not return to 100 percent as it was
before, but you should not get discouraged. Your breathing will improve
tremendously and you will feel better. Quitting smoking greatly reduces
the risk of many life-threatening diseases. Many human beings with COPD,
after kicking the habit, live productive, happy and long lives.